Chapter%202%20The%20Biological%20Basis%20of%20Behavior

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Chapter 2The Biological Basis of Behavior
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Introduction

• The brain is the control center of everything
  that we say and do!
• Complex organ
• Billons of cells
• Overlapping pathways and networks
• Plasticity ability to adapt to new environmental
  conditions
• Psychobiology biological bases of behavior and
  mental processes

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Introduction

• Neuroscience study of the brain and nervous
  system
• Neuropsychologists study brains influence on
  behavior

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Neurons

• Aka nerve cells
• Body contains approximately 100 billion
• Varies widely in size and shape
• Specialized to receive and transmit information

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Neuron Types

• Sensory neurons carry messages from sense organs
  to the spinal cord or brain
• Motor neurons carry messages from the spinal
  cord or the brain to the muscles and glands
• Interneurons carry messages from one neuron to
  another
• Glial cells hold neurons in place, provide
  nourishment, remove waste, prevent harmful
  substances to passing into the brain

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The Neural Impulse

• Yes-no, on-off electrochemical impulses
• Ions electrically charged particles
• Resting Potential electrical charge across a
  neuron membrane
• Excess () ions on outside, (--) on the inside
• Neural Impulse the firing of a nerve cell
• Polarization a resting neuron (--) on inside
• Depolarization inflow of () sodium ions
• sets off a chain reaction

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The Neural Impulse (cont)

• Threshold of Excitation the level the impulse
  must exceed to cause a neuron to fire
• All-or-none law the neuron will fire or it wont
• Absolute refractory period time after a neuron
  has fired that it WILL NOT fire not matter what
  the impulse

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The Synapse

• Neurons are NOT connected
• Tiny space between called synaptic space
• Terminal button end of axon branch
• Synaptic Vesicles tiny sacs in terminal button
  that release chemicals into the synapse
• Neurotransmitters chemicals release by the
  synaptic vesicles

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Neuron Toilet Worksheet
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Neurotransmitters

• Acetylcholine (Ach) acts where neurons meet
  skeletal muscles
• Role in arousal, attention, memory, motivation
• Linked to Alzheimers disease
• Dopamine assoc. with voluntary movement,
  learning, memory emotions
• Parkinsons disease
• Serotonin mood molecule (sets emotional tone)
• Half empty or half full
• Endorphins turn down neurons that transmit pain
  messages to the brain.
• review chart on page 54

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Neurotransmitters

• Imbalances have been linked to mental illness
• Schizophrenia (over abundance of dopamine)
• Depression (undersupply of serotonin
  norepinephrine)

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Nervous System Organization

• Includes the brain and the spinal cord
• Contains 90 of the bodys neurons
• Peripheral Nervous System division of the
  nervous system that connects the CNS to the rest
  of the body

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The Brain (cont.)
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The Brain (cont.)

• Cerebellum sense of balance and coordinating
  bodys actions

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The Limbic System

• The Limbic System is a doughnut-shaped system of
  neural structures at the border of the brainstem
  and cerebrum, associated with emotions such as
  fear, aggression and drives for food and sex. It
  includes the hippocampus, amygdala, and
  hypothalamus.

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Amygdala

• The Amygdala ah-MIG-dah-la consists of two lima
  bean-sized neural clusters linked to the emotions
  of fear and anger.

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Hypothalamus

• The Hypothalamus lies below (hypo) the thalamus.
  It directs several maintenance activities like
  eating, drinking, body temperature, and control
  of emotions. It helps govern the endocrine system
  via the pituitary gland.

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The Brain (cont.)

• Midbrain important for hearing and sight
• Pain is registered here (one of many)
• Thalamus relay station for incoming messages
  from the sense receptors (except for smell)
• Reticular Formation ALERT system network of
  neurons
• Pons- regulate sleep wake cycles
• Medulla regulates respiration, heart rate, blood
  pressure